1. Field of the Invention
The invention relates to a method of checking the printing of an ink jet printer.
2. Description of the Prior Art
The applications of this type of printer, in the industrial marking field in particular, increase regularly. Purely by way of illustration, there may in particular be mentioned the printing of "use by" dates on agro-alimentary products or batch numbers. Such marking is carried out more and more using ink jet printers of the "continuous deflected ink jet" type. The correct operation of such printers is governed by a number of relatively complex parameters which must be perfectly controlled if it is desired to obtain irreproachable printing quality. Despite the numerous improvements introduced these latter years in such printers, they are not proof against drifting of one or other of the parameters governing their operation, which may result in degradation of the quality of the writing. It is further known that, in most cases, such degradation of the writing quality has a typology in relation with the defective parameter. For example, the absence of an impact of droplets on the support to be printed may mean that the printing head needs cleaning. Similarly, to a fault in the positioning of the droplets there may correspond an abnormal ejection speed of the droplets or an incorrect speed of the movement of the head. Another problem may arise in so far as the size of the droplets is concerned. Furthermore, manufacturing or packing lines are more and more automated and permanency of the quality appears as of prime importance. Finally, since the marking function comes at the end of the production line, any defective marking results in unacceptable losses.